Cleanser for aluminum



Patented Aug. 9, 1932 UNITED STATES PATENT FFlE "WILMER CHARLES GANGLOFF, 0F CINCINNATI, OHIO, A$SIGNOR TO THE BRACKET! CHEMICAL COMPANY, OF CINCINNATI, OHIO, A COBPQRATION OF OHIO CLEANSER- FOIL ALUMINUlvI 1% Drawing.

The object of my invention is a cleanser for aluminum, that will combine a chemical action on some of the foreign substances with an abrasive action on othersthereof in a way that does not deleteriously afiect the aluminum by corrosion or by abrasion thereof.

Aluminum differs from most metals in its susceptibility to corrosion. It is usually very slightly or very vigorously attached by common corrosive agents. \Vhen exposed to the air a continuous and adherent film of oxide forms which protects the metal from further contact. This property, in addition to its lightness gives it distinct advantages over tin, iron and enamelware for household utensils. Its oxide coating does not protect it from vigorous attack by hydrochloric acid and alkalies. It does serve as a protection, however, in many instances where the corrosive agent would rapidly attack a clean aluminum surface. This protection is due to the low solubility coetlicient of aluminum in most reagents. Many instances are known where aluminum has been corroded by materials against the attack of which it is supposed to be resistant. Most experiences of this sort may be explained by the presence of an impurity in the reagent, such as the presence of chlorides in acids, the presence of alkali salts in ammonium hydroxide solutions, or contact with mercury salts. Any of these combinations will cause the rapid destruction of aluminum, particularly if the oxide coating should be broken by ascratch while in contact. Because these inherent chemical properties of aluminum are what they are, the cleaning of aluminum utensils is somewhat different from that of cleaning other utensils.

The discoloration occurring when merely water is boiled in a new aluminum utensil is well known to most housewives. This is surface attack with formation of oxide coating. Various foodstufi s cause stains. Products containing tannin bodies, iron or manganese are especially flagrant in producing brown stains. By far the greatest amount of discoloration on aluminum ware is caused by foodstufis scorching, burning or running over. Sugars turn to caramel and this in Serial No. 313,653.

turn to carbon. Sta-relies form dextrines and eventually carbon. Greases act as cementing agents. In addition gas flames deposit greases, carbon and assist in fixing the grease, discolorations and free carbon. Owing to the porous nature of aluminum these carbon particles and brown discolorations are partly burned into the pores. The areas covered with tree carbon burned into a hot utensil are always the hardest to remove. In al most every case an attempt is made to remove the stains and residues only after the utensil has cooled to room temperature and the pores have contracted.

Grease films cling to aluminum tenaciously and discolorations from a variety of sources appear that can only be removed by scouring.

I find that soap apparently does not affect aluminum.

Acids are undesirable in aluminum cleaners, because the majority of them attack aluminum, some lt'eebly, others vigorously and in some that do not attack aluminum. there are present impurities, which attack the metal.

Caustic alkalies are undesirable in an aluminum cleaner because they attack the metal vigorously.

Ammonia does not corrode aluminum, and it dissolves the products which cause many of the brown stains such as iron, manganese and tannic acid stains, on aluminum ware. Ammonia in nascent form is especially effective in dissolving such brown stains on aluminum ware.

My cleanser consists of a combination of substances that when moistened will produce ammonia in a nascent "form and will have an abrasive action that will remove the foreign substances that are not dissolved by the ammonia, without scratching the metal. The rate of evolution of ammonia must be rapid because in using such a mixture the evolution must be from a paste or colloidal damp mix. I have found that a mixture of the sesqui-carbonate of soda, tri-sodium phosphate, and ammonium chloride produces a desirable rate oi evolution of nascent ammonia from a paste or colloidal damp mix.

An abrasive to be satisfactory for aluminum must not be so hard as to mar the aluminum, which is of a soft nature and yet must have sufficient hardness to remove the carbon incrustations. Another point that must be borne in mind when using an abrasive in an aluminum cleaner, is that the cleaning of aluminum is usually done at the kitchen sink. An outstanding objection to the use of the current kitchen cleansers lies in the accumulation in the sink drains andtraps of these insoluble abrasives that are not attacked by the usual caustic soda pipe cleansers. Experience shows that frequently of the deposits in the clogged areas of sink drains and pipes is composed of silicious material that neither alkali nor acid would attack. Hence it is highly desirable in an aluminum cleaner to have an abrasive that is of an alkali soluble nature. Of the various forms of silica and the silicates, we find a variety known as opal. This is a natural colloidal silica, commonly occurring in nodular and stalactitic forms in cracks and cavities of volcanic rocks. It is of a hardness desirable and it is almost entirely soluble in hot solution of caustic alkali. I have found that form of silica if mixed with powdered pumice, if worked out to a consistent uniformity, produces an abrasive that is effective and unobjectionable. Pumice is a relatively mild abrasive and is composed of fragments of volcanic ash.

I have found it adi antageous, both for the production of the nascent ammonia and for the necessary abrasive actions, to have the cleanser in use, in the state of an emulsion. To maintain it in, an einulsive state and to provide a foam producing mass, a soap body is added.

Preferred proportions of my cleanser are:

Per cent Powdered pumice (passing 48 mesh) 25 Powdered SiO ((calcined) passing 48 mesh) 25 Sesqui-carbonate of soda 25 Trisodiuln phosphate (passing 20 mesh) 1O Powdered rosin base soap (passing 35 mesh) 10 Ammonium chloride (passing 20 mesh) 5 hat I claim is An aluminum cleanser comprising the following ingredients in substantially the following proportions Per cent Powdered pumice 25 Powdered SiO (calcined) Q5 Sesqui-carbonate of soda 25 Trisodium phosphate 10 Powdered soap 10 Ammonium chloride 5 In testimony whereof, I have hereunto subscribed my name.

\VILMER CHARLES GAN GLOFF. 

